Three electrode vacuum tube



y 31, 1932- J. BIGUET THREE-ELECTRODE VACUUM TUBE Filed Aug. 29, 1921 INVENTOR JACQUES mum 9 A I AT RNEY UNITED STATES;

PATENT -FFICE JACQUES BIGUET, OF LYON, FRANCE, ASSIGNOR TO RADIO CORPORATION OF AMERICA, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE THREE ELEG'IRODE VACUUM TUBE Application filed August 29, 1921, Serial No. 496,554, and in France October 23, 1915.

views of the apparatus, taken from two op- 'posite directions.

Figure 3 is a view of the stem with the leads sealed therein;

Figure 4 is a similar view showing the leads in their final shape before mounting the several electrodes;

Figures 5 and 6 illustrate perspective views of different types of plate electrodes that may be used; 7

Figure 7 shows one form of grid, and

Figure 8 is an alternative form of grid construction.

Into the bulb A is introduced and sealed into the neck of the bulb, in the same Way as in the ordinary incandescent lamp, a stem or support B on which are previously fixed or mounted the plate C, grid D and the filament E.

Each'of these elements is connected to the pins of the base F by conductors or leads sealed into the stem B. I

This stem, represented alone in Figure 3,

I is formed, as in ordinary lamps, of a flared glass tube with a press into which are sealed the leadsa, b, c, d,'each of which consists of an outside lead 6 of copper, a platinum or equivalent leading-in wire f, and an inside lead g, preferably of nickel or chrome-nickel.

These leads are during manufacture of the tube given the definite shape illustrated in Figure 4. The plate (Figure 5) is formed of a sheet of metal rolled intocylindrical shape and extended at the middle by one or two hooks m and m each provided with a recess, into which is introduced and pressed the correspondinglead 70. Another method of con-i struction can also be employed, such" as illustrated in Figure 6.

Insteadof a solid plate it canbe made of a trellis or tissue oftungsten wire as shown in Figure 7 i The coil or grid D illustrated in Figure 8 is composed of a wire of suitable diameter, preferably of tungsten or any other highly refractory metal, rolled helically and having two straight ends'which may be clamped or soldered to the ends of a cross bar it which is carried by the lead (Z, as indicated in Figure 4. I

The rectilinear filament is stretched be ween the two leads 2' and j, shown in the" same figure, which may be flattened or lengthened in any manner to give them simicient elasticity with a view to removing any danger of the filanients breaking. I,

The three elements of the device being con-" centrically placed give their maximum effectiveness, especially with regard to the plienomenon of saturation. Moreover, the squat shape of the whole ensures a greater solidity to the apparatus.

WVhen it is'employed as generator of maintain-ed waves, the energy expended can be such that the cylindrical plate may be carried to a high temperature; in that case it is advisable to employ a plate of reiractorymeta'l such as tungsten. Likewise, the conductors orileadsserving as support to the three ele ments may be of molybdenum or of tungsten their section may be rectangular instead of being circular, or divided into several wires of minimum section in order to ensure their cooling. p

The power-of the apparatus may be in creased by giving the three elements a greater length, but it the two points of attachment of the coil or grid Dare too far away, the

"latter may give way or be distorted in an injurious manner. In that case it is supported by another and more rigid wire also coiled into a helix but of greater pitch than" the grid D and coiled in the opposite direction The device illustrated in Figure 9 allows the use of a very fine coil or grid, relatively long and practically undistortable.

What I claim is:

1. A three-electrode vacuum tube having a rectilinear filament, a helical grid surrounding said filament and a cylindrical plate sur- 5 rounding said grid, a conductor arranged entirely outside of said plate for supporting the grid only at each of its extremities, and a lead-in wire connected to said conductor.

2. A three-electrode vacuum tube having a rectilinear filament, a grid circular-shaped in cross-section and formed of a single continuous wire enclosin said filament, a cylindrical plate surrounding said grid, a conductor arranged entirely outside said plate and parallel to the longitudinal axis thereof for supporting the grid only at each of its extremities, and a lead-in wire connected to said conductor.

3. In an electron-discharge tube, a helical grid electrode, means for supporting said grid electrode comprising a conductor arranged in spaced parallel relation to the axis of the grid electrode and connected to the electrode extremities only, and a lead-in wire joined to said conductor.

4. An electron discharge device comprising a press, concentric grid, filament and plate electrodes supported above said press, I a pair of adjacent lead-in conductors for said filament centrally arranged within said press, a lead-in conductor for said grid disposed within said press to one side of said filament lead-in conductors, and a lead-in con,- ductor for said plate disposed within said press to the other side of said filament lead-in conductors and remotely from the grid leadin conductor, said lead-in conductors forming the sole su porting means for said electrodes.

5. An e ectron discharge device havin a filament, a helical grid surrounding said filament and a cylindrical plate surrounding said grid, a conductor substantially coextensive with and arranged entirely outside of said plate for supporting the grid, and a lead-in wire connected to said conductor.

In testimony whereof I aflix my signature.

J. BIGUET.

fiERTIFIfiATE 0F CGRRECTION.

Patent No. 1,861,107. May 31, 1932.

JACQUES BiGUET.

It is hereby certified that error ape-ears in the printed specification of the above numbered patent requiring correction as follows: Page 1, lines 54 and 55, strike out the werds "as shown in Figure 7", line 56, for the figure "8" read 7 and line 98, for "9" read 8; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office. I

Signed and sealed this 18th day of October, A. D. 1932.

M. J; Moore, (Seal) Acting Commissioner of Patents. 

